Photographic apparatus



' o. WITITEL 2,169,013

PHOTOGRAPHIC APPARATUS Filed July-21, 1937 mun/1111f I ATTORNEYS.

Patented Aug. 8, 1939 UNITED STATES PATENT OFFlCE PHOTO GRAPHIC APPARATUS poration of New Jersey Application July 21, 1937, Serial No. 154,839

4 Claims.

The present invention relates to film-type phonographic apparatus employing a scanning light beam and more particularly to an arrangement for properly controlling such beam.

In apparatus for recording or reproducing sound on a transparent film different standards prevail, some apparatus being designed to handle film having the sound track extending along one margin of the film while other apparatus is adapted for film having the sound track along its other margin. It is desirable to have a single apparatus which will accommodate either type of film and the obvious solution is to thread the film through the apparatus in such manner that the sound track is in alignment with the scanning beam. When so threaded some films will have its emulsion or record surface facing the optical system while other films will have such surface facing away from the optical system thus requiring a refocusing of the optical system Whenever a change is made to a different type of film.

It is an object of the invention to provide an apparatus with which such adjustment of the scanning beam may be quickly and accurately made.

Another object of the invention is the provision for a sound optical system of a mounting arrangement which permits removal and replace ment of the system without disturbingits adjusting mechanism.

Another object of the invention is the provision of a novel adjustable optical system which can be shifted accurately to proper axial position for a sound track carried on either face of a film.

Other objects and advantages of the invention will appear from the following description when read in connection with the accompanying drawing in which:

Fig. 1 is a partial view in perspective of an apparatus incorporating a mounting arrangement for the optical system embodying the invention;

Fig. 2 is a transverse sectional view on line 2-2 of Fig. 1; and

Fig. 3 is a plan View of the mounting means shown in Fig. 1 and with a modified adjusting arrangement.

In the drawing the invention is shown as applied to sound reproducing apparatus having a rigid frame In which supports a mount l! for a suitable optical system including a lens [2 for focusing light from a source l3 in a narrow line on a sound track I4 carried by a transparent film l5. Suitable means such as a drum l6 moves the film IS in any well known manner so that the sound record l4 modulates the light which it transmits and this modulated light is directed by prism l'l onto a light sensitive device l8 which translates it into varying electrical impulses which may later be converted into sound in the usual way.

' The frame member ID is provided with a notch having an under face l9 and a front face 20 (see Fig. 2) against which a key 23 carried by the mount H is pressed by spring members 21 and 22, respectively. The faces l9 and 20 are so positioned with respect to the drum l6 that the optical system mount II is properly positioned vertically and laterally with respect to the sound track Id. The top wall of the mount ll engages an under face 24 of the frame ID to insure greater stability. This key 23 is accurately made and accurately positioned on the mount 1 I so that its sides are parallel to the axis of the lens system carried by the mount I I and perpendicular to the sound track at the point it is scanned. The retaining spring 22 urges the key 23 against the front face 20 of the frame member Ill and may be pivotally secured to the frame I!) by means of a headed pin 25 so that it may be rotated upwardly to permit lateral movement of the key 23, thus permitting the mount l l to be withdrawn sidewise.

The key 23 is made long enough to extend beyond the frame In and this extending portion is provided with a notch to provide two opposing faces 26 and 21 separated from one another by a predetermined distance. The head 28 of a screw 29 extends into this notch when the mount H is in position and the axial thickness of the head 28 is accurately made smaller than the distance between the two faces 26 and 21 by an amount equal to the thickness of the film i which is to be employed in the apparatus. The spring member 2|, which urges the mount upwardly, is pivotally secured to the frame IE1 by a pin 30 and its free end which bears against the underside of the mount H is provided with an open slot 3| into which extends a downwardly extending stud 32 carried by the lower face of the mount H. The member 2| has secured thereto a resilient arm 33 which, in a manner soon to be described, tends to rotate the member 2! about its pivot 3|] in either direction as desired. This resilient arm 33 extends through an opening 34 provided in another portion of the frame Hi. This opening 34 is provided with two upwardly projecting lugs 35 to form three recesses 36, 31 and 38 into any one of which the resilient arm 33 may selectively be moved by means of a suitable knob 39 provided on its outer end.

The arrangement just described is so constructed that when the arm 33 is positioned in recess 36, as shown in Fig. 1, the resilience of the arm 33 rotates the member 2! about its pivot to move the mount H and its key 23 toward the sound track i i until the face 21 engages the head 28 of the screw 29. Movement of the arm 33 to a position in recess 38 reverses the direction of spring pressure to shift the mount H rearwardly until the abutting face 26' engages the head 28 of the screw 29 in which position the optical system will be focused on the front face of the film Hi. When the arm 33 is in the recess 37 it is under no stress and in this position the mount 5 i may readily be removed after the spring member '22 is moved out of the path of the key 23, the open slot Si in the spring 25 permitting the escape of the pin 32 carried on the under face of the mount H.

The screw 2% is screw threaded into the frame member ii) for obtaining original adjustment of the head 28 to the proper position for predetermining the two positions to which the mount ll may be shifted. After such original adjustment of the screw it remains fixed and the shifting of the mount ii quickly and accurately secured by changing the position of the spring arm 33.

The arrangement shown in Fig. 3 differs from that of Fig. 1 only in the device for placing strain on the spring arm 33 to provide the biasing force to the mount II. In this embodiment, a cam 40 eccentrically mounted on a shaft 4! and rotatable therewith by means of a winged head 42 is shiftably secured to the frame (not shown) of the apparatus. A rectangular frame 43 carried by the free end of the arm 33 fits over the cam 40 so that rotation of the cam 49 through 180 imparts the desired change to the tension of the spring 33. Rotation of the cam 36 through from the position shown corresponds to positioning the arm 33 in the middle recess 31 in Fig. 1 and in this position there is no bias to the mount II.

In the embodiments shown in the drawing the mount H is biased to the position for scanning a sound record 14 carried on the face of the film i5 farthest removed from the incident light. If the next film to be reproduced has its record facing the incident light the necessary refocusing is quickly and accurately obtained by shifting the arm 33 to the recess 38 or as shown in Fig. 3 by rotating the cam 40 through It is to be understood that the embodiment shown and described in detail is merely illustrative of my invention and that many other arrangements are obviously available for selectively biasing the mount for the optical system in each of two predetermined positions for the purpose described.

Although the invention has been shown as applied to a mount capable of assuming two focused positions and an intermediate free position for easy removal it will be obvious that the device of the invention may advantageously be employed when only one focused position is desired in which case the free position would permit easy removal for any purpose such as cleaning and just as easy return to a position of accurate focus.

What I claim as new and desire to secure by Letters Patent of the United States is:

i. In a sound head, a support, an optical system mount removably secured to the support, guide means on the support for determining the lateral position of said mount, means for yieldably pressing said mount against the guide means,

stop means for determining the axial position of said mount, an abutment carried by said mount and adapted to engage the stop means, and releasable resilient means for biasing said abutment into firm engagement with said step means.

2. A sound unit for motion picture projectors comprising a film scanning position, an optical unit for producing a scanning image, positioning means adjustable to alter the position of said unit longitudinally of its axis, and means for shif ing said unit along its axis a predetermined fixed amount with respect to said positioning means, whereby the scanning image may alternately be made to occupy two predetermined positions with respect to said positioning means,

3. A sound head adapted to scan selectively a sound record carried on either face of a transparent support of predetermined thickness, comprising means for moving the sound record and its support past a point of translation, means including an optical system for forming a line of light, adjustable means for moving the optical system along its axis to cause the line of light to coincide with said translation point, and means for quickly shifting the optical system along its axis and with respect to said adjustable means a distance substantially equal to the thickness of the transparent support for the sound record.

4. Film-type phonographic apparatus comprising an optical system adapted to form a luminous image, means for adjusting the optical system axially to focus said image upon one surface of the film, and means for shifting said system axially with respect to said adjusting means by a distance substantially equal to the thickness of the film whereby said image may be quickly focused upon the other surface of the film.

OTTO WITTEL. 

